Greylag Geese staging and wintering in France 37
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 24–39
same period, as the wintering habits have
changed. Observations of neck-banded
geese seen in France are too few for an
analysis at the individual level, but data on
neck-banded geese from areas where they
are studied more intensively (
e.g
. at the
breeding/marking areas in southwest
Sweden, Norway and some Dutch staging
areas) made it possible to study changes in
migration phenology. For instance, Nilsson
(2006) found that in recent years Greylag
Geese from southwest Sweden have arrived
earlier in spring, and migrated south later,
compared with the early years of his long-
term study. In Norway, Greylag Geese now
arrive about three weeks earlier than during
the 1970s (Pistorius
et al
. 2006) but, unlike
the Swedish birds, they also leave Norway
about three weeks earlier (A. Follestad,
unpubl. data). The earlier arrival of the
Greylag Geese to the Nordic breeding areas
can be attributed to warmer winters and
earlier springs, whereas changes in the
timing of autumn migration are more likely
a result of changes in agriculture, albeit that
these changes may also be related to weather
conditions. In Norway the harvest is earlier
compared to former years, whereas in
Sweden, in addition to the winters being
milder, the geese have also changed their
feeding habits and used leftovers from the
sugar beet harvest (which provides a high
carbohydrate diet) during the entire late
autumn from the 1990s onwards (Nilsson &
Kampe Persson 2013). The changes in
migration timing is apparent for the entire
flyway as 20% of the Greylags known to
winter in Spain arrived in the Swedish
breeding areas before the end of February
in 1986–1990, this proportion increasing to
40% for the period 2001–2005 (L. Nilsson
unpubl. data). In the latter period,
c
. 5% of
the Greylag Geese from southwest Scania
wintering in Spain were recorded back in
Sweden during January. During the same
five-year period, an additional 12% were
recorded back in the first days of February.
Thus, up to one-fifth of the Greylag Geese
migrating from Sweden to wintering areas in
Spain probably pass through France on
spring migration before the end of January.
During the early years of the study, Nilsson
& Persson (1996) found that Greylags
wintering in the Netherlands had
significantly higher breeding success than
those migrating via France to winter in
Spain. This difference may be due to a
shorter migration for the birds wintering in
the Netherlands (and their earlier return to
breeding areas), but may also be related to
disturbances at staging and wintering areas
in France and Spain, where hunting pressure
is higher than in the Netherlands.
Acknowledgements
The study was supported by grants from
Office National de la Chasse et de la Faune
Sauvage (to LN). It is based mainly on the
observations of neck-banded Greylag
Geese reported to the
database by thousands of voluntary
observers. We also thank Bernard
Deceuninck, the Ligue pour la Protection
des Oiseaux and Wetlands International for
the map of the winter distribution of
Greylag Geese in France, Michel Gauthier-
Clerc (Tour du Valat) for providing
unpublished goose counts and the National
Museum of Natural History in Paris for the
ringing recoveries data.
